VrayBlendMtl’s Blend amount gets bugged if I use VrayColor2Bump map in the coat material. In Adv everything is fine but in RT CUDA it doesn’t matter if I use a blend color 1 RGB or 254 RGB, the material will render the same. As soon as I remove the VrayColor2Bump map from the coat material, the blend amount starts working correctly again. Please check the images below. All render settings are at default. I can send you the scene if you need it.
